[alexandre-vl]

Closes #1017

The problem

Settings spans 12 pages, 53 settings rows and 24 shortcuts, with no way to search them: you guess the page, then scan it. Some rows sit where nobody would look, and ⌘K only offers Open settings. Details in #1017.

The change

Search settings, a field under Back. ⌘F (Ctrl+F) focuses it from anywhere in Settings, and its hits replace the section list.

• Index (settings/search.rs): a table beside the pages giving each row's page, block, title and the words people search by that the title lacks. It also lists every shortcut where it's recorded, and every page. the_index_and_the_pages_agree draws every page and fails when a page shows a row the index lacks, or the index lists a row its page doesn't anchor.
• Ranking follows the palette's thread search. Every word must match: title 100, the row's own terms 40, block 30, page 20, half again at a word start, and an exact title outranks the rest. A word nothing spells may match one a single edit off (two from 8 letters, never under 4), always below real matches. Cloud and Billing aren't searched while they're hidden.
• Landing (settings/search/reveal.rs): a pick opens the page, glides the row a third of the way down (motion::SCROLL_GLIDE), then washes it with the accent (150 ms in, 900 ms held, 600 ms out). Rows wear a SearchAnchor and each page one page_reveal, so pages keep no state, listeners or timers for it. Reduced motion jumps. Scrolling mid-glide hands the page back. A hidden row (Autosave delay, Microphone…) lands on its toggle, and a row that hasn't drawn after 1.5 s is let go.
• Keyboard: ↑↓ walk the hits; Enter or a click opens one, and the field keeps the keyboard for the next pick. Escape clears the query, then closes Settings. Leaving Settings any way clears it.

Screens

Dark	Light

Idle, ⌘F hint	Typo	Shortcuts	No results

theme lists titles, then the page. notifcations still finds Notifications and its rows. math size + Enter glides Appearance to its last row, which glows. Captured by the new settings-search-fixture example: the production Shell offscreen, with real ⌘F and Enter key dispatch (README).

Tests

• settings::search (12): ranking, typos, highlights, hidden pages.
• settings::search::reveal (10): landing math, glide, hand-back, reduced motion, fallback, seek limit, window scoping. One drives a real scroll container.
• shell::settings_search (6), on the real Shell: the keyboard flow end to end, shortcut hits, the keyboard kept across a pick (Appshots, a click), Enter on the clear button, leaving Settings any way, and the index/pages agreement.
• Full -p zeron-ui --lib on this head (macOS): 1856 passed, 0 failed, plus attachments:: 33 passed with --test-threads=1. One earlier run failed pull_requests::tests::pull_request_repository_picker_keeps_selection_and_cancels_detection by 0.5px. That test isn't touched here, and it fails 1 in 5 isolated runs.

Not verified: the glide's smoothness in an interactive window (the frames are offscreen), and Cloud and Billing rows, which draw only with an account. Screen readers don't hear the active hit: focus stays in the input, which isn't the rows' ancestor, so gpui ignores aria_active_descendant. The ⌘K palette shares this.

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[zeronsh]

Security audit clean: UI code, tests and screenshots only. No dependency, build.rs or CI changes, no network or process calls, no unsafe, and the PNGs carry no trailing data. Rebased onto main and added follow-ups: the Providers rows (Native subagents from #1046, Completion, Update policy) are indexed and anchored, and the agreement test now draws an expanded provider. The clear button gets a tooltip and focus ring, the empty state is the palette's, the field lines up with the nav, and ⌘F no longer waits on a closing account menu. ⌘F is bound only inside Settings; nothing else in the app uses it, and the shortcut recorders and user bindings still take it first. Local: cargo test -p zeron-ui --lib 2006 passed, 0 failed; app and fixture build; no clippy warnings on added lines.